First version of Codecs and Converters.

tests/lib/codec/codec2_test.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:codec';
+
+import 'package:expect/expect.dart';
+
+main() {
+  final RAW = '["122ç",50,50,231]';
+  final ENCODED = const [91, 34, 49, 50, 50, 195, 167, 34, 44,
+                         53, 48, 44, 53, 48, 44, 50, 51, 49, 93];
+  final UTF8 = Encoding.UTF8;
+  Expect.listEquals(ENCODED, UTF8.encode(RAW));
+  Expect.equals(RAW, UTF8.decode(ENCODED));
+
+  Expect.listEquals([], UTF8.encode(""));
+  Expect.equals("", UTF8.decode([]));
+
+  final JSON_ENCODED = RAW;
+  Expect.equals(JSON_ENCODED, JSON.encode(["122ç", 50, 50, 231]));
+  Expect.listEquals(["122ç", 50, 50, 231], JSON.decode(JSON_ENCODED));
+
+  // Test that the reviver is passed to the decoder.
+  var decoded = JSON.decode('{"p": 5}', reviver: (k, v) {
+    if (k == "") return v;
+    return v * 2;
+  });
+  Expect.equals(10, decoded["p"]);
+  var jsonWithReviver = new JsonCodec.withReviver((k, v) {
+    if (k == "") return v;
+    return v * 2;
+  });
+  decoded = jsonWithReviver.decode('{"p": 5}');
+  Expect.equals(10, decoded["p"]);
+
+  // Test example from comments.
+  final JSON_TO_BYTES = JSON.fuse(Encoding.UTF8);
+  List<int> bytes = JSON_TO_BYTES.encode(["json-object"]);
+  decoded = JSON_TO_BYTES.decode(bytes);
+  Expect.isTrue(decoded is List);
+  Expect.equals("json-object", decoded[0]);
+}